Objective of this thesis is to identify potential energy savings regarding engine heating of cars within the Jämtland-Härjedalen county, northern Sweden. This could contribute to energy consumption reduction goals of Sweden. Potential energy savings are defined by comparing the current energy consumption with the energy consumption of different energy saving scenarios in terms of behavioural change and technological choices. Energy consumption, both current and potential is modeled in excel based on data derived from quantitative investigation and literature review. Engine heating is identified as an energy consumer, the energy saved by fuel consumption reduction (7,77 TJ/year) does not overcome the invested energy to heat engines (26,36 TJ/year). Engine heating reduces engine wear, fossil fuel consumption (0,34 TJ/year) and emissions currently. Regarding the choice of technology using more automatic time adjustment reduces energy consumption, engine wear, emissions and fossil fuel consumption. Other scenarios show a compromise between energy consumption reduction on one side and fossil fuel consumption reduction in combination with reduced engine wear and emissions on the other side.